aThree new functionalized UiO-66-X (X = -SO 3 H, 1; -CO 2 H, 2; -I; 3) frameworks incorporating BDC-X (BDC: 1,4-benzenedicarboxylate) linkers have been synthesized by a solvothermal method using conventional electric heating. The as-synthesized (AS) as well as the thermally activated compounds were characterized by X-ray powder diffraction (XRPD), diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, thermogravimetric (TG), and elemental analysis. The occluded H 2 BDC-X molecules can be removed by exchange with polar solvent molecules followed by thermal treatment under vacuum leading to the empty-pore forms of the title compounds. Thermogravimetric analysis (TGA) and temperature-dependent XRPD (TDXRPD) experiments indicate that 1, 2 and 3 are stable up to 260, 340 and 360°C, respectively. The compounds maintain their structural integrity in water, acetic acid and 1 M HCl, as verified by XRPD analysis of the samples recovered after suspending them in the respective liquids. As confirmed by N 2 , CO 2 and CH 4 sorption analyses, all of the thermally activated compounds exhibit significant microporosity (S Langmuir : 769-842 m 2 g −1 ), which are comparable to that of the parent UiO-66 compound. Compared to the unfunctionalized UiO-66 compound, all the three functionalized solids possess higher ideal selectivity in adsorption of CO 2 over CH 4 at 33°C.

The amine-decorated microporous metal-organic framework CAU-1 was readily synthesized and activated using a home-made efficient protocol. It exhibited a high heat of adsorption for CO 2 , high CO 2 uptake capacity, and an impressive selectivity for CO 2 over N 2 . At 273 K and up to 1 atm, CO 2 uptake capacity can reach as much as 7.2 mmol g À1 . Comparatively, the CH 4 and N 2 uptakes at 273 K and 1 atm were only 1.34 mmol g À1 and 0.37 mmol g À1 , respectively. The CO 2 /N 2 selectivity was 101 : 1 at 273 K. The isosteric heat of adsorption (Q st ) for CO 2 was $48 kJ mol À1 at the onset of adsorption, and it decreases to $28 kJ mol À1 at higher CO 2 pressures. Furthermore, CAU-1 can adsorb 2.0 wt% and 4.0 wt% hydrogen at 77 K under 1 atm and 30 atm, respectively. The adsorption characteristics of CAU-1 for methanol investigated in situ with a quartz crystal microbalance (QCM), indicated that this particular MOF structure can be used as a highly sensitive sensor for methanol detection such as direct methanol fuel cells. Recently, the basic properties of amine functionalized MOF were tested in Knoevenagel condensation reactions, 14,15 and Couck et al. 16 found that at low surface coverage, the CO 2 /CH 4 selectivity of the amine functionalized MIL-53(Al) was larger than that of the parent MIL-53(Al).

Various MOFs with tailored nanoporosities have recently been developed as potential storage media for CO 2 and H 2 . The composites based on Cu-BTC and graphene layers were prepared with different percentages of graphene oxide (GO). Through the characterization analyses and gas adsorption experiments, we found that the nanosized and well-dispersed Cu-BTC induced by the incorporation of GO greatly improved the carbon dioxide capture and hydrogen storage performance of the composites. The materials obtained exhibited about a 30% increase in CO 2 and H 2 storage capacity (from 6.39 mmol g À1 of Cu-BTC to 8.26 mmol g À1 of CG-9 at 273 K and 1 atm for CO 2 ; from 2.81 wt% of Cu-BTC to 3.58 wt% of CG-9 at 77 K and 42 atm for H 2 ). Finally, the CO 2 /CH 4 and CO 2 /N 2 selectivities were calculated according to single-component gas sorption experiment data.

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A new surface tension model based on a thermodynamic analysis on a vapor−liquid surface in an aqueous concentrated electrolyte solution has been proposed. The relation between the surface tensions and the osmotic coefficients of electrolyte solutions which are calculated by the Pitzer equation is established. The surface tensions of 46 single-electrolyte solutions are correlated with only one parameter and the overall average deviation is 1.22%. On the basis of the parameters obtained by correlating the surface tensions of single-electrolyte aqueous solutions, the surface tensions of mixed- and single-electrolyte solutions at different temperatures can also be predicted with deviations of 1.50%. In all cases investigated, good agreement is observed, even for the systems containing high concentrations of electrolytes.

Phase-transition diagrams of three CaSO4 phases, namely, dihydrate, hemihydrate, and anhydrate, in the HCl−CaCl2−H2O system are successfully constructed making use of a recently developed OLI-based chemical model. After initial validation of the model by comparison to experimentally determined CaSO4 phase-transition points in H2O or pure HCl solutions, the phase-transition border between dihydrate and anhydrite and that between dihydrate and hemihydrate was obtained by calculating the solution supersaturation (or scaling tendency according to OLI). The constructed phase-transition diagrams show three main regions, namely, regions I, II, and III. In region I, dihydrate is stable, while anhydrite is stable in regions II and III. Dihydrate is metastable in region II, while hemihydrate is metastable in region III. An increase in HCl and/or CaCl2 concentration causes the metastable region of HH to expand at the expense of DH. This has the result of lowering the corresponding transition temperatures.

Solubilities of calcium sulfate dihydrate, hemihydrate, and anhydrite in concentrated HCl, CaCl 2 , and their mixed aqueous solutions were measured by using the classic isothermal dissolution method at the temperature range from (283 to 353) K. The concentration investigated for HCl is up to 12 mol‚dm -3 and for CaCl 2 is up to 3.5 mol‚dm -3 at room temperature. The solubility of CaSO 4 phases in all cases investigated was found to increase with the temperature increment with the exception of anhydrite in CaCl 2 solutions. In pure HCl media, increasing the acid concentration in the range of (0.0 to 3) mol‚dm -3 HCl causes the solubility of CaSO 4 ‚2H 2 O or CaSO 4 to increase reaching a maximum value and then decrease gradually with further increasing HCl concentration. In the concentrated range of (8 to 12) mol‚dm -3 HCl, the solubility of CaSO 4 ‚ 1 / 2 H 2 O decreases with acid concentration. In HCl + CaCl 2 mixed media, the addition of CaCl 2 causes the solubility of all three phases to decrease due apparently to common ion effect.